488 research outputs found

    Impacts of invasive Opuntia cacti on wild mammals in Kenya

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    In this thesis, I explored the impacts of invasive plants on animal behaviour, using the invasion of Opuntia cacti in Laikipia County, Kenya, as a specific case study. In the opening chapter, I introduced the topic of biological invasions, addressing essential background material and identifying key knowledge gaps. In the second chapter, I focused on the impacts of invasive plants on animal behaviour, an important – yet neglected – topic. I synthesised the disparate literature on invasive plants’ behavioural impacts within a novel mechanistic framework, revealing that invasive plants can cause profound behavioural changes in native animals, with ecological consequences at multiple scales. I also found that environmental context played an important role in moderating how an invader’s modes of impact translate into behavioural changes in native species, and how these behavioural changes then generate ecological impacts. Finally, I identified priority research questions relating to the behavioural impacts of invasive plants. Invasive plants’ behavioural impacts can manifest as changes to the occurrence patterns of native animals. In Chapter 3, I used simulations to explore model selection in occupancy models, which are a powerful tool for studying the patterns and drivers of occurrence. Specifically, I investigated the consequences of collider bias – a type of confounding that can arise when adding explanatory variables to a model – for model selection using the Akaike Information Criterion (AIC) and Schwarz Criterion (or Bayesian Information Criterion, BIC). I found that the effect of collider bias, and consequently the inferential and predictive accuracy of the AIC/BIC-best model, depended on whether the collider bias was present in the occupancy or detection data-generating process. My findings illustrate the importance of distinguishing between inference and prediction in ecological modelling and have more general implications for the use of information criteria in all linear modelling approaches. In Chapter 4, I applied the mechanistic framework from Chapter 2 and the modelling conclusions from Chapter 3 to the problem of understanding Opuntia’s behavioural impacts in Laikipia County. Specifically, I used camera traps to explore the effects of Opuntia on occupancy and activity for eight key mammal species. I found that the effects of Opuntia varied among mammal species and depended on the spatial scale of the Opuntia cover covariate. These findings have important implications for the conservation of endangered mammal species in the region, the future spread of Opuntia through seed dispersal, and interactions between wildlife and local communities. In Chapter 5, I addressed key knowledge gaps pertaining to Opuntia’s biotic interactions with native animals. First, I quantified the relationship between height and fruiting in O. engelmannii and O. stricta, finding that height was positively related to fruiting for both species, and that the relationship was stronger for O. engelmannii than for O. stricta. I also found that local habitat variables were related to height and/or fruiting in both Opuntia species. Second, I documented the interactions between animals and Opuntia using camera traps. In so doing, I confirmed the importance of interactions that were previously thought to be important, while also highlighting interactions which have previously received little attention in the published scientific literature

    Mindfulness-based cognitive therapy v. group psychoeducation for people with generalised anxiety disorder: randomised controlled trial

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    Background: Research suggests that an 8-week mindfulness-based cognitive therapy (MBCT) course may be effective for generalised anxiety disorder (GAD). Aims: To compare changes in anxiety levels among participants with GAD randomly assigned to MBCT, cognitive–behavioural therapy-based psychoeducation and usual care. Method: In total, 182 participants with GAD were recruited (trial registration number: CUHK_CCT00267) and assigned to the three groups and followed for 5 months after baseline assessment with the two intervention groups followed for an additional 6 months. Primary outcomes were anxiety and worry levels. Results: Linear mixed models demonstrated significant group × time interaction (F(4,148) = 5.10, P = 0.001) effects for decreased anxiety for both the intervention groups relative to usual care. Significant group × time interaction effects were observed for worry and depressive symptoms and mental health-related quality of life for the psychoeducation group only. Conclusions: These results suggest that both of the interventions appear to be superior to usual care for the reduction of anxiety symptoms

    CAMAU Project: Research Report (April 2018)

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    ‘Learning about Progression’ is a suite of research-based resources designed to provide evidence to support the building of learning progression frameworks in Wales. ‘Learning about Progression’ seeks to deepen our understanding of current thinking about progression and to explore different purposes that progression frameworks can serve to improve children and young people’s learning. These resources include consideration of how this evidence relates to current developments in Wales and derives a series of principles to serve as touchstones to make sure that, as practices begin to develop, they stay true to the original aspirations of A Curriculum for Wales – A Curriculum for Life. It also derives, from the review of evidence, a number of fundamental questions for all those involved in the development of progression frameworks to engage

    CAMAU Project: Research Report (April 2018)

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    ‘Learning about Progression’ is a suite of research-based resources designed to provide evidence to support the building of learning progression frameworks in Wales. ‘Learning about Progression’ seeks to deepen our understanding of current thinking about progression and to explore different purposes that progression frameworks can serve to improve children and young people’s learning. These resources include consideration of how this evidence relates to current developments in Wales and derives a series of principles to serve as touchstones to make sure that, as practices begin to develop, they stay true to the original aspirations of A Curriculum for Wales – A Curriculum for Life. It also derives, from the review of evidence, a number of fundamental questions for all those involved in the development of progression frameworks to engage

    Open Problems and Fundamental Limitations of Reinforcement Learning from Human Feedback

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    Reinforcement learning from human feedback (RLHF) is a technique for training AI systems to align with human goals. RLHF has emerged as the central method used to finetune state-of-the-art large language models (LLMs). Despite this popularity, there has been relatively little public work systematizing its flaws. In this paper, we (1) survey open problems and fundamental limitations of RLHF and related methods; (2) overview techniques to understand, improve, and complement RLHF in practice; and (3) propose auditing and disclosure standards to improve societal oversight of RLHF systems. Our work emphasizes the limitations of RLHF and highlights the importance of a multi-faceted approach to the development of safer AI systems

    Marketing as a means to transformative social conflict resolution: lessons from transitioning war economies and the Colombian coffee marketing system

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    Social conflicts are ubiquitous to the human condition and occur throughout markets, marketing processes, and marketing systems.When unchecked or unmitigated, social conflict can have devastating consequences for consumers, marketers, and societies, especially when conflict escalates to war. In this article, the authors offer a systemic analysis of the Colombian war economy, with its conflicted shadow and coping markets, to show how a growing network of fair-trade coffee actors has played a key role in transitioning the country’s war economy into a peace economy. They particularly draw attention to the sources of conflict in this market and highlight four transition mechanisms — i.e., empowerment, communication, community building and regulation — through which marketers can contribute to peacemaking and thus produce mutually beneficial outcomes for consumers and society. The article concludes with a discussion of implications for marketing theory, practice, and public policy

    Utilisation of an operative difficulty grading scale for laparoscopic cholecystectomy

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    Background A reliable system for grading operative difficulty of laparoscopic cholecystectomy would standardise description of findings and reporting of outcomes. The aim of this study was to validate a difficulty grading system (Nassar scale), testing its applicability and consistency in two large prospective datasets. Methods Patient and disease-related variables and 30-day outcomes were identified in two prospective cholecystectomy databases: the multi-centre prospective cohort of 8820 patients from the recent CholeS Study and the single-surgeon series containing 4089 patients. Operative data and patient outcomes were correlated with Nassar operative difficultly scale, using Kendall’s tau for dichotomous variables, or Jonckheere–Terpstra tests for continuous variables. A ROC curve analysis was performed, to quantify the predictive accuracy of the scale for each outcome, with continuous outcomes dichotomised, prior to analysis. Results A higher operative difficulty grade was consistently associated with worse outcomes for the patients in both the reference and CholeS cohorts. The median length of stay increased from 0 to 4 days, and the 30-day complication rate from 7.6 to 24.4% as the difficulty grade increased from 1 to 4/5 (both p < 0.001). In the CholeS cohort, a higher difficulty grade was found to be most strongly associated with conversion to open and 30-day mortality (AUROC = 0.903, 0.822, respectively). On multivariable analysis, the Nassar operative difficultly scale was found to be a significant independent predictor of operative duration, conversion to open surgery, 30-day complications and 30-day reintervention (all p < 0.001). Conclusion We have shown that an operative difficulty scale can standardise the description of operative findings by multiple grades of surgeons to facilitate audit, training assessment and research. It provides a tool for reporting operative findings, disease severity and technical difficulty and can be utilised in future research to reliably compare outcomes according to case mix and intra-operative difficulty

    A randomized, double-blind, placebo-controlled trial of coenzyme Q10 in Huntington disease

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    Objective: To test the hypothesis that chronic treatment of early-stage Huntington disease (HD) with high-dose coenzyme Q10 (CoQ) will slow the progressive functional decline of HD. Methods: We performed a multicenter randomized, double-blind, placebo-controlled trial. Patients with early-stage HD (n = 609) were enrolled at 48 sites in the United States, Canada, and Australia from 2008 to 2012. Patients were randomized to receive either CoQ 2,400 mg/d or matching placebo, then followed for 60 months. The primary outcome variable was the change from baseline to month 60 in Total Functional Capacity score (for patients who survived) combined with time to death (for patients who died) analyzed using a joint-rank analysis approach. Results: An interim analysis for futility revealed a conditional power of <5% for the primary analysis, prompting premature conclusion in July 2014. No statistically significant differences were seen between treatment groups for the primary or secondary outcome measures. CoQ was generally safe and well-tolerated throughout the study. Conclusions: These data do not justify use of CoQ as a treatment to slow functional decline in HD

    Telephone based self-management support by 'lay health workers' and 'peer support workers' to prevent and manage vascular diseases: a systematic review and meta-analysis

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    Background: Improved prevention and management of vascular disease is a global priority. Non-health care professionals (such as, ‘lay health workers’ and ‘peer support workers’) are increasingly being used to offer telephone support alongside that offered by conventional services, to reach disadvantaged populations and to provide more efficient delivery of care. However, questions remain over the impact of such interventions, particularly on a wider range of vascular related conditions (such as, chronic kidney disease), and it is unclear how different types of telephone support impact on outcome. This study assessed the evidence on the effectiveness and cost-effectiveness of telephone self-management interventions led by ‘lay health workers’ and ‘peer support workers’ for patients with vascular disease and long-term conditions associated with vascular disease. Methods: Systematic review of randomised controlled trials. Three electronic databases were searched. Two authors independently extracted data according to the Cochrane risk of bias tool. Random effects meta-analysis was used to pool outcome measures. Results: Ten studies were included, primarily based in community settings in the United States; with participants who had diabetes; and used ‘peer support workers’ that shared characteristics with patients. The included studies were generally rated at risk of bias, as many methodological criteria were rated as ‘unclear’ because of a lack of information. Overall, peer telephone support was associated with small but significant improvements in self-management behaviour (SMD = 0.19, 95% CI 0.05 to 0.33, I2 = 20.4%) and significant reductions in HbA1c level (SMD = -0.26, 95% CI −0.41 to −0.11, I2 = 47.6%). There was no significant effect on mental health quality of life (SMD = 0.03, 95% CI −0.12 to 0.18, I2 = 0%). Data on health care utilisation were very limited and no studies reported cost effectiveness analyses. Conclusions: Positive effects were found for telephone self-management interventions via ‘lay workers’ and ‘peer support workers’ for patients on diabetes control and self-management outcomes, but the overall evidence base was limited in scope and quality. Well designed trials assessing non-healthcare professional delivered telephone support for the prevention and management of vascular disease are needed to identify the content of effective components on health outcomes, and to assess cost effectiveness, to determine if such interventions are potentially useful alternatives to professionally delivered care

    Self-love and sociability: the ‘rudiments of commerce’ in the state of nature

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    Istvan Hont’s classic work on the theoretical links between the seventeenth-century natural jurists Hugo Grotius and Samuel Pufendorf and the eighteenth-century Scottish political economists remains a popular trope among intellectual and economic historians of various stamps. Despite this, a common criticism levelled at Hont remains his relative lack of engagement with the relationship between religion and economics in the early modern period. This paper challenges this aspect of Hont’s narrative by drawing attention to an alternative, albeit complementary, assessment of the natural jurisprudential heritage of eighteenth-century British political economy. Specifically, the article attempts to map on to Hont’s thesis the Christian Stoic interpretation of Grotius and Pufendorf which has gained greater currency in recent years. In doing so, the paper argues that Grotius and Pufendorf’s contributions to the ‘unsocial sociability’ debate do not necessarily lead directly to the Scottish school of political economists, as is commonly assumed. Instead, it contends that a reconsideration of Grotius and Pufendorf as neo-Stoic theorists, particularly via scrutiny of their respective adaptations of the traditional Stoic theory of oikeiosis, steers us towards the heart of the early English ‘clerical’ Enlightenment
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